The prior art teaches door spacers having the general utility disclosed herein, but none of the door spacers of the prior art exhibit the improvements of the present invention.
U.S. Pat. No. 3,714,738 issued to Koslow et al. on Feb. 6, 1973 teaches sliding glass door retainer means to fill the space between the sliding glass door and the inside of the upper track retaining the door so that the sliding glass door can not be lifted vertically from the outside and thus removed by unauthorized persons. The door spacer of Koslow, best seen in FIG. 2 thereof, comprises oppositely tapered wedges 4 and 5, one of which is either mounted to the sliding door or the top track thereof, and the other of which rides up on the first wedge to adjust its vertical height above the door. When the wedges have been suitably adjusted, they are fastened together to preserve their relative alignment. The overall result of Koslow is to form an essentially rectilinear solid block which is fixed either to the door or the top track guiding the door and disposed in the space between the top track and the door in order to prevent the door from being lifted vertically into the top track.
U.S. Pat. No. 4,054,398, issued to Prohaska on Oct. 18, 1977 teaches the use of a spacer block such as 12, or a portion of another structure such as 8, fixed to the interior of the top track of the sliding door in order to prevent the sliding door from being raised as described above. Prohaska teaches adjustment of the vertical thickness of the spacer block by providing a block with a rectangular transverse cross-section so that the spacer block can be oriented with either a longer side or a shorter side vertical. Prohaska also teaches that plates may be added to the spacer block to change its effective height. Finally, Prohaska recognizes that double faced adhesive tape can be used to fix the latch assembly 8 within the top track of the sliding door. The primary utility of the device of Prohaska is to lock the sliding door with respect to horizontal sliding motion thereof.
U.S. Pat. No. 4,084,290, issued to Lymar et al. on Apr. 18, 1978 teaches a sliding door and window stop generally comprising stacked, horizontally disposed plates with adhesive applied between them. The vertical height of the device of Lymar is adjusted by peeling away a suitable number of the sandwiched layers to leave a residual structure with the appropriate thickness to limit the upward movement of the sliding door or window while allowing free sliding thereof.
The art thus illustrates that it is well known to provide a blocking member between the top of a sliding door and an inside portion of its top track in order to prevent the door from being lifted out of its bottom track into its top track, and then removed. The purpose of such device is to foil burglary or other unauthorized removal of sliding door or windows. The prior art devices can all be classified as solid blocks of material interposed between the top of the sliding door and the interior of its top track.